Crab and Watercress Tart

To the pastry
4 tbsp cold butter, diced, plus extra for greasing
125g / 4 1/2 oz plain flour, plus extra for dusting
pinch of salt
ice-cold water

To the filling
300g / 10 1/2 oz fresh white and brown crab meat, thawed if frozen
1 bunch of watercress, leaves picked from the stems
50ml / 2 fl oz milk
2 large eggs plus 3 egg yolks
200ml / 7 fl oz double cream
salt and pepper
1/2 tsp ground nutmeg
1/2 bunch of fresh chives, snipped
2 tbsp freshly grated Parmesan cheese

Lightly grease a 23cm / 9in loose-based fluted tart tin. Sift the flour with the salt into a food processor, add the butter and process until the mixture resembles fine breadcrumbs. Tip the mixture into a large bowl and add a little cold water, just enough to bring the dough together. Turn out onto a lightly floured work surface. Roll out to 8cm / 3 1/4 in larger than the tin. Line the tin with the dough and trim the edge. Line the tart shell with baking paper and fill with dried beans. Chill in the refrigerator for 30 minutes.

Remove the tart shell from the refrigerator and bake in a preheated oven, 190ºC / 375ºF / Gas Mark 5, for 10 minutes. Remove the paper and beans and bake the tart shell for 5 minutes more. Remove from the oven and reduce the oven temperature to 325ºF / 160ºC / Gas Mark 3.

Arrange the crab meat and watercress in the tart shell, reserving a few watercress leaves for garnishing. Whisk the milk, eggs and egg yolks together in a bowl. Bring the cream to simmering point in a saucepan and pour over the egg mixture, whisking all the time. Season with salt and pepper and stir in the nutmeg and chives. Carefully pour over the crab and watercress and sprinkle over the cheese. Bake for 35-40 minutes until golden and set. Let the tart rest for 10 minutes before serving, garnished with the reserved watercress.